Find the length of the line of $\displaystyle y = \frac {2}{3} x^\frac {3}{2}$ from x=0 to x=2
i used the formula, i dont know if i was supposed to use u substitution, but i got $\displaystyle 2 \sqrt{3}$
ok ... $\displaystyle \frac{2}{3}(1+2)^{\frac{3}{2}} = 2\sqrt{3}$
but ...
what did you get when you evaluated $\displaystyle \frac{2}{3}(1+x)^{\frac{3}{2}}$ using the lower limit of integration, $\displaystyle x = 0$ ?
... or did you just assume it would have a value of 0 ?